[Patch bpf 1/3] skmsg: introduce sk_psock_get_checked()
From: Cong Wang <hidden>
Date: 2021-09-24 22:05:29
Also in:
netdev
Subsystem:
bpf [l7 framework] (sockmap), networking [general], networking [sockets], the rest · Maintainers:
John Fastabend, Jakub Sitnicki, Jiayuan Chen, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Linus Torvalds
From: Cong Wang <redacted> Although we have sk_psock_get(), it assumes the psock retrieved from sk_user_data is for sockmap, this is not sufficient if we call it outside of sockmap, for example, reuseport_array. Fortunately sock_map_psock_get_checked() is more strict and checks for sock_map_close before using psock. So we can refactor it and rename it to sk_psock_get_checked(), which can be safely called outside of sockmap. Cc: John Fastabend <john.fastabend@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jakub Sitnicki <jakub@cloudflare.com> Cc: Lorenz Bauer <redacted> Signed-off-by: Cong Wang <redacted> --- include/linux/skmsg.h | 20 ++++++++++++++++++++ net/core/sock_map.c | 22 +--------------------- 2 files changed, 21 insertions(+), 21 deletions(-)
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14ab0c0bc924..d47097f2c8c0 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h@@ -452,6 +452,26 @@ static inline struct sk_psock *sk_psock_get(struct sock *sk) return psock; } +static inline struct sk_psock *sk_psock_get_checked(struct sock *sk) +{ + struct sk_psock *psock; + + rcu_read_lock(); + psock = sk_psock(sk); + if (psock) { + if (sk->sk_prot->close != sock_map_close) { + psock = ERR_PTR(-EBUSY); + goto out; + } + + if (!refcount_inc_not_zero(&psock->refcnt)) + psock = ERR_PTR(-EBUSY); + } +out: + rcu_read_unlock(); + return psock; +} + void sk_psock_drop(struct sock *sk, struct sk_psock *psock); static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index e252b8ec2b85..6612bb0b95b5 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c@@ -191,26 +191,6 @@ static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock) return sk->sk_prot->psock_update_sk_prot(sk, psock, false); } -static struct sk_psock *sock_map_psock_get_checked(struct sock *sk) -{ - struct sk_psock *psock; - - rcu_read_lock(); - psock = sk_psock(sk); - if (psock) { - if (sk->sk_prot->close != sock_map_close) { - psock = ERR_PTR(-EBUSY); - goto out; - } - - if (!refcount_inc_not_zero(&psock->refcnt)) - psock = ERR_PTR(-EBUSY); - } -out: - rcu_read_unlock(); - return psock; -} - static int sock_map_link(struct bpf_map *map, struct sock *sk) { struct sk_psock_progs *progs = sock_map_progs(map);
@@ -255,7 +235,7 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk) } } - psock = sock_map_psock_get_checked(sk); + psock = sk_psock_get_checked(sk); if (IS_ERR(psock)) { ret = PTR_ERR(psock); goto out_progs;
--
2.30.2